The present application relates to the field of medical apparatus including medical imaging apparatus and treatment system, particularly to an X-ray apparatus and system; and relates to the collimation of the position of the body of a patient through collimation of an irradiation landmark on the body surface of the patient.
Radiography usually requires precise collimation of a particular position on the body surface of a patient. Precise and fast collimation is the key point of successful irradiation and helps to reduce the time of the whole irradiation process and to decrease patient discomfort.
Currently, the procedure of collimating a patient of a digital radiography system with automatic collimation function (such as a GE Definium 8000 system, see FIG. 1) generally includes the following steps: (i) selecting a patient; (ii) selecting an initial position for the overhead tube suspension (OTS) (as shown in the dropdown menu A); (iii) pressing and holding the automatic collimation button B (see the control panel), the OTS starting to move towards a target position, releasing the button when the OTS moves to the target position; (iv) instructing the patient to the specific position (before the chest-radiography stand, on the bed or other position); (v) manually moving and/or rotating the tube to collimate at the irradiation landmark on the body surface of the patient and re-confirming the field of view (FOV) of the irradiation and so on. When confirming the FOV, the central ray should be collimated at the irradiation landmark on the body surface of the patient. For example, as shown in FIG. 2, for a lying position, the central ray (5) emitted by the tube (8) is usually perpendicular to the patient and at a particular position directly over the irradiation landmark (3) on the body surface, the irradiation landmark (3) on the body surface is located at the center of the FOV (4) of irradiation.
From this it can be seen that this type of system cannot realize completely automatic collimation of a patient. Wherein, although the OTS moves towards a target position automatically, the collimation of the movement and/or rotation of the tube is manually performed. Precise collimation of an irradiation landmark on the body surface of a patient by using this method takes a long time and the work flow is rather complicated.
U.S. Pat. No. 5,590,665 discloses a laser guided lesion localization apparatus, but the apparatus does not perform collimation at an irradiation landmark on the body surface of a patient. Another U.S. Pat. No. 5,598,269 discloses a movable laser guided alignment apparatus for assisting a CT apparatus in collimation, which includes two beam sources of a laser line beam source and a laser fan beam source. However, the apparatus is complex in structure and inconvenient in operation.